These two principles have now been incorporated into the
Micro tremors in the voice, which are often not detected
by the human ear, produce frequency modulations, which are
The amplitude of the upper and lower sidebands of the frequency
spectrum of the voice is also measured.
The results are analysed and shown visually by the columns
of LED lights which range from green (low tension) to red
The Truth Machine accurately measures changing stress levels
in the voice but as each individual's voice reacts differently
it is not infallible; the lighting of red LEDs, high stress,
is indicative of lying however!